Manufacture of glycols and glycol derivatives.



, possessed KARL P-MOELBOY, OF WASHINGTOlfl DISTBICT OF COL UMBIA,ASSIGNOB T0 CHEMICAL DEVELOPMENT CQMPANY, A CORPORATION OF manurjac'runnor eLYcoLs AND LYcoL nnnrvnrrvns'.

No Drawing.

To all whom it may concern."

Be it known that I, KARL P. MCELROY, a citizen of the United States,residing at Washington, in the District of Columbia, have inventedcertain new and useful Improvements in the Manufacture of Glycols andGlycol Derivatives, of which the following is a specification; V

This invention relates to the manufacture of glycols and glycolderivatives; and it comprises a process wherein a 'dihalid of an olefinis heated under pressure with a liquid comprising water and a salt ofcalcium with a weak acid; all as .more fully hereinafter set forth andas claimed.

The glycols and the various glycol de-- rivatives such as the acetates,are bodies of properties adapted to make them useful in the arts, butno-cheapand efficient method of producing them is in use. It iscomparatively easy to roduce dlhalids by direct reaction of bromm orchlorin on the double bond hydrocarbons or olefins, and these dihalidspossess in some respects the properties of esters of glycols; Butsaponification of. these dihalids is quite diflicult and it 'is stillmore diflicult to obtain good yields of the sa'ponified products, theglycols. This is for a variety of reasops, one

being that the reaction of the dihalids with alkali hydroxids in lieu,of being, as might be expected, a direct substitution of hydroxyl forhalogen is apt to take' another course and resultin the withdrawal ofhydrogen and one atom of halogen with formation of an unsaturatedcompound. Ethylene, for example, easily unites directly with bromin orchlori'n to form a dihalid, but this dihalid on treatment with KOH or'NaOH gives the corresponding' -vinyl derivatives in eater or lessproportion. Potassium car 'onate' works better than the hydroxide butmust be used in dilute solution and the yield for this reason (glycolbeing quite volatile with water vapors) and because of the formation ofsome amount of vinyl compounds, is always very poor. A furtherinconvenience in the'potassium carbonate method .arises .from the factthat potassum chlorid or bromid crystallizes out of the mother liquorson concentration of the resultin glycol solutions and 'makes the materiainconvenientto handle.

For the stated reasons, in the laboratory production of glycols (thesebodies are not Specification of LettersPatent. Patent d M 19, 191

' Application ala March 29,

1913. Serial No. 757,582. I

made commercially) it is usual to employ an mdirect method ofproduction, that of first making an acetate from the dihalid (usuallythe bromid) with an alcoholic so-' ence of a limited amount of water andat a rather high temperature.

By so doing I secure anumber of simultaneous advantages.

Lime is not as strong-a base as soda or potash and does not have thesame tendency to form unsaturated compounds; nor do its salts dissociatein solution to form free alkali to the same extent; The dissociation ofpotassium carbonate solution in the usual direct method is presumed tobe responsible for the formation of vinyl compounds. On

treating an olefin bromid or chlorid with a I lime salt one product ofthe reaction is of course the corresponding calcium halid; and

both the chlorid andthebromid of calcium are readily soluble,hygroscopic salts forming solutions with water which retain theirfluidity even at relatively high temperatures. here is not therefore thenecessity,

as with potassium and sodium salts, of removing crops of crystals fromtime to tlme.

lermanently fluid reaction mixtures, from which gl cols or their estersmay be easily recovere may-be made without the use of undue amounts ofwater.

By operating under pressure at temperatures of, say, 100 'C. to 150 C.ina closed container the usual difficulty of slowness of reaction.disappears and'furthermore it is not necessary to employ. a solvent ofolefinhalid, such as alcohol, to keep such halidin the sphere ofreaction. Alcohol may be used in the present invention and isuseful;

but it may also be dispensed with. While either a dibromid or adichlorid may be used in the present invention, in 1 practice I prefer,the dichlorids both because of the less bulk and because calciumchlorid is a better component of the final.- v

reaction mixture than is calcium bromid.

Though other calcium salts of weak'acids may be employed, I prefer thecarbonate or the acetate; the former when'making g1;- cols direct andthe latter when making t e glycol acetates. With carbonates, theevolution of CO causes extra pressure with the "reaction Vessel whichmay/therefore be provided with venting means leading through acondenser.

T he present process may be employed with any olefin dihalid from anysource. I It may, for example, be used in converting ethylene dichlorid(Dutch liquid) or dibromid into glycol or into ethylene acetates. Theethylene used in making the dihalid may be made from alcohol or fromacetylene,

Propylene, butylene, etc., halids may be converted in a similar Way.Various liquid olefins, such as are contained in petroleum or suchproducts asfcracked gasolenes.

' may first be chlorinated or brominated and after freeing ofconden'sable bodies, on direct treatment with chlorin'yields' a'mixtu-reof dichlori'ds Which may be treated by the present process to yieldmixtures of glycols or glycol derivatives which are'of advantageousproperties. Of course the dichlorids may be fractionated into ethylene,propylene, etc., dichlorids, and these then separately treated; but theusual mixture of ol'efins of such oil gas gives a mixture of chloridswhich in turn gives properties.

In one specific embodiment'of my inventi0n,'I may take such a mixture ofchlorids formed from a petroleum gas and place it in any suitablecontainer capable of withstanding heat and pressure. To the chlorids Imay add about an equal amount of fine powdered calcium carbonate andat'least enough water to make a pulpy mass. The container is now closedand an agitator set in motion. Agitation should be active. The mixtureis now heated up to, say, 115 to 130 C. for a period of, say, twoor'three hours, or longer. As the reaction produces C(). ,.so1negas maybe vented off from time to time, the venting being best "through areflux condenser and past an ordinary condenser to prevent escape of asmuch volatiles as possible from the container and to recover thosevapors which are vented off with the gas. As these chlorids are quitevolatile, some are apt to escape in this venting off, going past thereflux. CO pressurein the container as is convenient, in addition tothe-steam pressure corresponding to the heat as this facilitates andquickens the reaction as well as obviating glycol .mixtures ofadvantageous It is advantageous to' keep as much any tendency towardthe' vinyl producing reaction alluded to. The CO makes the carbonatemore soluble in water and thereby quickensv the action.

As the reaction in the container goes forward, the calcium carbonate isgradually converted into calcium chlorid which forms a heavy 'solutionwith the water present and the glycol formed, and in this heavy soluition 'emulsification .and efficient contact of the oily chloride iscomparatively easy. The container being closed, there is no loss ofeither chlorids or of glycol except in venting off, and this little maybe'recoveredin the stated manner.

At the end of the reaction, With the quantitles indicated, the oilychlorids and the calcium carbonate will have disappeared and .there willremain a solution of calcium chld' rid and the glycol formed. Only alimited amount of water having been used, there is usually no necessityof concentrating this distillate for concentration, it being borne inmind however that glycol is considerably .more volatile with water vaporthan isglycerin. The mixed glycols from oil gas olefinssuffer less lossthan pure ethylene glycol solutions. The calcium chlorid solutionis'partieu-larly well adapted for the steaming operation. In lieu ofsteaming,- of course vacuum distillation may be used; or currents ofhydrogen, blue water gas,'or other indifferent gas maybe employed. Butthe steaming is simple and efl'ective. 7

Any form. oficalcium carbonate, such as air slaked lime, ground chalk,precipitated carbonate of lime, etc., may be employed,

but I find the precipitated carbonate the most reactive.

' As the calcium ehloridexerts .a facilitating action upon the glycolforming reaction, in'making up a charge it is often desirable -to usesome of the mother liquor from a prior operation in lieu of part of thewater. In.

concentrating the distillate after steaming,

the water vapors volatilizing may a'dvan-' tageously be condensed andthe condensate used .in forming steam for steaming out or in lieu ofwater in making up a charge as this enables saving suchglycol as mayhave volatilized therewith.

An advantageous method of operation is to concentrate the condensatefrom the steaming operation in a closed container, thereby obtaining aconcentrated glycol, and to use the vapors from the concentrating afresh finished charge.

In the stated operation using the dihalids apparatus in lieu of steamfor steaming out ene and propylene, glycols, with some butyethylenedichlorid and 'propylenedichlorid .lene glycols; .a mixture which isdesirable for use as such since for manypurposes its "ene glycol. If theoily chlorids from the oil gas have been fractionated to recover pureseparately, and the separate fractions then reaction mixture quickensthe reaction-but has some lncldental disadvantages. The reactlonmlxtures described are all properties are better than those ofpureethylneutral and non-corrosive and the operations can be readilyperformed in iron, 'steel,v or copper vessels.

' If desired, heacetates can be first made in the present process andthese then saponitreated in the manner described, then the fied withlime to give gl cols, whereby calproducts will naturally be the pureglycols. clum acetate is recovere for re-use.

If pure glycolsare desired it is betterto fractionate the halids than totry to sepa-- ratethe 'glycols after formation.

If the olefin bromids-are used in lieu of 1 the. chlorids, thetemperatures'may be somedllute glycol solution is obtained.

what lower and the time of operation shorter, and the relativeproportions must At temperatures around 200 C. the reaction is muchquicker, but with these high temperatures the amount of water presentshould be considerably increased and a more Another source of the halidsfor producing ethylene glycol and other ethylene esters be changed.Using the mixed bromids from under the present invention is calciumcarbidoil gas, a good proportion is one part caland'six to eight,-ormore, parts of water.

If I substitute calcium acetate, such as commercial gray acetate oflime, in the described operatlon I will produce glycol Carbid dust orwaste or other form of carbid 26 cium carbonate, two parts of mixedbromids can be used to produce acetylene, this acetylenesemi-hydrogenated to produce ethylene by hydrogen .inthe' presence ofcatalysts such as copper, nickel, etc, (proper precautions being takento restrain the reaction acet'ates. For example,Imay mix1 00 parts Whichotherwise-may go to ethane), the

of the oilychlorids from the oil gas mentioned with 180-190 parts ofcommercial gray acetate and 350' to 500 parts of water and heat withagitation to 120 to 150C. for three or four hours, or until a sampleshows complete conversion of the oily chlorids. No CO being produced inthis reaction, venting off is not necessary. At theend of the re-.action, the glycol acetate may be steamed ofl ethylene chlorinated orbrominatcd and the halid converted aspreviously described. This givespure ethylene derivatives.

What I claim'is:-- 1 '1. The process of converting olefin dihalids intouseful products WlllCh. comprises heating such dihalids under pressurein the'presence of a liquid comprising water and of a salt ofa Weak acidanda base, such 5 and recovered. If half the quantity of calbase beingone which gives a hygroscopic cium acetateis employed a doublechloracetate ester is produced. y using 90 parts of acetate, parts ofcarbonate and 100 parts of oily chlorids, the monoacetates of theglycols are produced.

Other calcium salts of weak acids may be employed, such as lactate,butyrate, for-v mate, borate, .tartrate, etc, to obtain correspondingesters.

While strontlum and barium salts may be used, they are not as desirablein the present invention as the calcium compounds for the reason that,the barium and strontium chlorids and .bromids do not have the deolefins of oil gas under pressure in the presence of aliquid comprisingwater and of a salt of a. weak'acid' and a base, such base being. onewhichgives a hygroscopic halid sal4t.

Theprocess of producing useful prod- 50 sired physicalrelations to waterof the cor uctswhich comprises heating halids of the responding calciumsalts. On the other hand, salts of the remainingalkaline earth,

magnesia may well be used since magnesium chlorid and bromidhave thesame desirable calcium salt of a weak acid.

Y '5. The process of .producmg useful prodproperties in, this respect asthe calcium ucts; which comprises heating under pressalts. Dolomiticlimestone may be used in preparing the.carbonat e used.

Zinc carbonate or oxycarbonate may be used as substitute for calciumcarbonate as it. also gives hygroscopic halid salts. Zinc salt of a weakacid.

sure a mixture of olefin dihalids correspond.- .ing to the olefins of011 gas in the presence of a liqui decomprising water'and a calcium 6.The process of producing useful products which comprises heating underpressure a mixture of olefin dihalids correspond- 7 ing to the olefinsof oil gas in the presence of a liquid comprising water and calcium 05*Addition of a little sodium sulfate acetate.

Y 5 of a liquid comprising water and calcium 7. The process of producinguseful prode In testimony whereof, I aflix my signaucts WhiChcompnsesheating under-presture in the presence of two subscribing 10 sure amixture of olefinrdihalids correspondwitnesses. ing to the olefins ofoil gas in the presence K P MCELROY acetate; such pressure being greaterthan Witnesses:

* e that due to the temperature of the liquid so PERCY HQMooRE,

heated. HILDA SCHOEN THAI.

